Will I have to reinstall OS when I switch Gigabyte mobos?

[stebbinsd]

I previously used a Gigabyte GA-970a-UD3P. I recently bought a Gigabyte GA-970a-D3P. In other words, it's the same model number, but without the "U." The motherboard layouts are 100% identical to one another, as far as the naked eye can tell.

Will I have to reinstall the OS? Or are the models similar enough that I can get decent performance without reinstalling?

 

[Phillip Corcoran]

You might get away with it (not re-installing), only way to know for sure is to try it.

If Windows refuses to start, or it runs unstable or errors keep popping up, you'll know to re-install it.

 

[SkyNetRising]

Or are the models similar enough that I can get decent performance without reinstalling?

You should be able to do that. Boot mode settings and sata controller mode in BIOS have to be made the same.
And your windows will get deactivated because of this hardware change.